I like the idea of the chessboard, but I think its pretty simple. Something to make it more interesting might be when its activated an anomalous entity appears and asks your wish and you have to make a bet against the "opponent" entity, something it gets if you lose. Perhaps, when its activated the game starts really simple but gets more difficult the more moves are played, and the "opponent" changes the rules, making it nigh impossible to beat. As the game progresses, the stakes get higher and higher, your prize and cost both increases, and at a certain point the "opponent" delivers an ultimatum, and the challenger can leave and lose nothing, or continue and not be able to leave until the game ends.

Just some ideas for expansion, because a wish giving chess board is not complex enough on its own.

I like the first idea. It's sort of a Series I idea so some people might think it's too simple, but if done well I'd vote up. That I can find, there's currently only two chessboards in the SCP foundation so it's an object that isn't often anomalous. The way in which it grants wishes could be interesting as well. Perhaps it doesn't grant the wish in exactly the desired way? Not quite monkey's paw but something in line with that.

I'm confused what exactly you mean by the second idea so I can't really say anything about that one.

The first one is too utilitarian for my taste, and it's also a plot point from Kekkai Sensen. Any skip that deals with wishes really needs to be creative as hell, but a simple chess match to earn wishes is not nearly enough in that regard.

I'm not sure what you mean by the second idea? A shaver that grows hair on it?

sorry for making it so unclear.
The 2nd idea is about a shaver, except that instead of shaving the hair, it actually grows it in the way shaved hair looks like. (I'm not sure if i made it clear, but sorry.)